Spark-plug.



R. R. BROWN.

SPARK PLUG.

APPLICATION IILEDNOV. 4, 1911.

Patent-,ed ,May 26, 1914.

l Il I.

UNITED "STATES ,PATENT ormon- BICHARD RALPH BROWN, OF BELVIDERE, ILLINOIS, ASSIGNOR 0F ONE-HALF TO WILLIS S. BROWN, 0F BELVIDERE, ILLINOIS.

SPARK-PLUG.

Specification of Letters Patent.

Patented May 26, 1914.

Application filed November 4, 1911. Serial No. 658,515.

To all whom it may concern Be it known that I, RICHARD RALPH BROWN, a citizen of the'United States, residing at Belvidere, in the county of Boone and State of Illinois, have invented certain new and useful Improvements in Spark- Plugs, of which the following is a full, clear, and exact specification.

This invention relates to spark plugs for jump spark ignition systems or circuits, and it has for its o-bject to provide a spark plug which will be economical to manufacture, simple in construction, durable, eflicient in operation, and rea'dily adjustable to various conditions, as well as being of neat appear- In the saiddrawingsFigure 1 is a longitudinal section of a spark plug embodying this invention; Fig. 2 is a detail elevation, partly broken away, of the gland; and Fig. 3 is a similar view of a modified form of gland.

1 is a hollow member which is screw threaded on its exterior, as shown at 2, so that it may be screwed into the spark plug aperture of an engine. This member 1 constitutes a housing for the porcelain insulator 3. The member l is formed with a shoulder 4, and the insulator 3 with a shoulder 5, and between these two shoulders is interposed a gasket 7 adapted to make a gas-tight joint when the shoulders are pressed together. The insulator 3 is also formed with a tapering projection 8, which is surrounded by a gland 9 having a taper'- ing feather edge 10, engaging the tapered projection 8 and adapted t-o yield to irregularities in pressure resulting from irregularities in contour, or otherwise, when the gland 9 is forced over the tapered projection 8, the gland 9 being formed of comparatively soft or yielding metal, so that it will also constitute a packing where it engages the projection 8. The gland 9 is screw threaded on its exterior andv screwed into the screw threaded interior of the member 1, as far as may be necessary to securely hold the porcelain 8 in place and prevent leakage of gas.

The outer extremity 'of the gland 9 is formed with an electrode 11. This is preferably of the form of a bridge looping outwardly from the gland 9, and having a central aperture 12, into which the inner electrode 13 projects. This bridge electrode member 11 also constitutes a means whereby thegland 9 may be readily screwed into place, and possesses the further important advantage of being susceptible of being formed of any desired length to adapt the spark plug to engines of different design, it being often the case that the electrode must be extended farther inward with some engines than with others. IVhere this is the case the end has been accomplished in a measure by merely extending the member 1 and the electrode 13 inwa-rdly the desired extent. This, however, results in a long member 11 which is objectionable. In some cases instead of extending the member l, a long extension or electrode has been secured to the end thereof. This results in an objectionably long and iiimsy electrode. With this invention, however, the member 1 may he used for engines of various designs, the glands 9 being formed with electrodes 1l of different lengths, and the inner electrodes 13 being accordingly extended or shortened, as may be necessary.

The extension 8 is formed with a socket 14 for the reception of a shoulder 15 on the stem 1G of the inner electrode, the stem being smaller than the shoulder 15, so as to ferm a seat for a gas-tight gasket 17. The stem 1G is held in place by nuts'lS as usual, or other-wise.

In the form 0f gland shown in Fig, 3, instead of using a soft yielding material for the inner end thereof, it is formed of elastic material, and the inner end is slotted at suitable intervals, as shown at 19, resulting in elast-ic tongues 20, which embrace the tapered projection 8 and hold it firmly and centrally while forcing the porcelain up to its seat against the shoulder 4. These tongues Q0 yield to irregularities of pres sure resulting from the porcelain and the gland being out of true center while the gland is being screwed into place.

IVith a plug thus constructed it will be seen that all of the screw threads on the member l are formed on one and the same end thereof, leaving the upper outer end entirely free from project-ing nuts or glands. Consequently, the manufacture of the plug is considerably simplified and cheapened, because of the fact that all of the threading may be done by one operation, or one setting in the screw machine, making it possible also to form the shoulder 4, and nish the interior of the member 'l without removing the latter from the machine.

That I claim is:

In a spark plug ofthe class described, the combination oi' a hollow open end body member having an inturned shoulder at its upper end and internal screw threads at its lower end portion, an insulator removably positioned in said hollow body member and having an enlargement abutting said shoulder, an electrode supported by said insulator and extending beyond the lower end of said body member, and a. one-piece hollow gland member adapted to be screwed into the lower end of said body member and having a tapered split upper end portion which yieldingly engages and clamps said 'tapered enlargement against said shoulder and having an integral open-sided loop extension arranged in sparking relation to said electrode and provided with an aperture forming therewith a spark cap.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses, on this lst day of November A. D. 1911.

RICHARD RALPH BROWN.

Witnesses THOMAS A. WILLARD, CHARLES D. Loor. 

